


Vulnerable

by crush (beekeepercain)



Category: Supernatural
Genre: Bottom Sam, Dark, Dubious Consent, M/M, Sexual Content, Transformation, Vampire Dean
Language: English
Status: Completed
Published: 2017-05-02
Updated: 2017-05-02
Packaged: 2018-10-27 00:13:25
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,880
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10797702
Author URL: https://archiveofourown.org/users/beekeepercain/pseuds/crush
Summary: Dean goes missing - and when he comes back, he's not the same Dean that left.





	Vulnerable

**Author's Note:**

> May prompt (vampire!Dean) for [Wincest Writing Challenge](wincestwritingchallenge.tumblr.com) on Tumblr. :>

* * *

 

Sam's instincts woke him up like a jolt of electricity rushing through his spine. He stayed still, although his breathing had already turned shallow and his body was tense, and he couldn't tell for certain if the intruder had spotted the shift yet. Quietly and without opening his eyes completely, he tried to peer into the darkness to find his enemy, while his hand moved ever so slowly towards the gun hidden underneath the mattress with its handle poking out just enough to ensure he could grab it quickly. Then, the intruder chuckled - and Sam recognised his voice.

"It won't work anymore, Sammy," Dean's voice told him quietly.

His hand went limp on the mattress, and after holding in his breath for a moment, Sam sat up in the bed. He slid his legs down from the bed and tried the hard floor underneath them although it seemed to be swaying and dared to stand up, but he hesitated before moving further. There was something off about Dean - something was _wrong._ He'd feared as much: Dean had been gone for a week without a trace, and Sam had spent that whole time trying to track him down to no avail. And now that he was there... he didn't seem like the brother Sam had known his whole life.

"Dean?" he called out, his voice breathless and as tense as his body was.

Dean nodded.  
"Yeah," he said, still with that soft tone that seemed to echo with regret, "It's me."

"Where have you - what happened?" Sam asked, stepping to the side to turn on the light.

Before he could reach it - really, in barely a blink of an eye - Dean was there, his hand on Sam's, stopping him from touching the light switch. Sam's hand retreated slowly, and he could smell Dean now, but it wasn't the same comforting scent he was used to anymore. It was... like Dean had stayed in a basement for an extended amount of time, long enough for the damp, cold smell to stick to his clothes. And there was an undertone to that smell; a bitter, coppery smell. It made Sam shudder even as Dean's cold fingers lifted from his arm.

"I need you to do me a favour," Dean spoke, ignoring Sam's question, and the regret in his tone leaked over to the side of despair only ever so slightly, but Sam caught up on it immediately.

"Dean -"

"Sam," Dean cut him off before he could speak, "I need you to end me."

Sam swallowed. He fell back towards the bed and sat down there, and before him, Dean knelt down to remain at his level or a little below it, submissive and pleading.

"I got caught, see," he continued, another joyless chuckle escaping him before a sigh did, "Rookie mistake, didn't check my corners. I got dragged into the nest. Got bitten. Got infected."

"With what?"

"You know with what, Sam. They made me drink - there's no way back. I can barely hold it together; just being here, being around you, I can smell your blood, Sam. I can hear your heartbeat. There's no way to explain this and there's - there's nothing else you can do to help me. So - do me a favour, baby brother, alright? Do what a hunter should do."

Sam could barely breathe. He was suddenly feeling lightheaded and his world was swaying worse than before, and his heart was racing, and he was all too aware of Dean knowing it. He wanted to argue, or deny everything that Dean was telling him, but he couldn't; he could smell it, he could hear it in Dean's voice, and inside, he just knew it to be true. But how? They hadn't been hunting vampires. They hadn't been hunting, period. This was just a stop on the way south. That was all this had been. How had this happened?

"Dean, there's - there's got to be another way."

Dean snarled. He stood up again, paced a couple steps to gather himself.

"What way, Sam? There's only one cure, and you know it won't work once the vampire has fed. I've fed. I had no choice. It's over, Sam. God - please. Just - I can't do it myself. There's no way. It's either you, or someone else, someone I don't know, someone who doesn't care who I am. I'd rather - Sam, I'd rather it be you. If I got to choose - the last thing I see on this earth would be you. Who else? You're all that I've got, the only family I have left, the only friend I ever really had."

He breathed funnily for a second before forcing himself to continue.

"I don't want to die alone," he confessed in a suffocated voice, falling back on the bed opposite of Sam.

Sam was cold. His whole body was shaking and his palms and his back were all wet with sweat, and the draft in the motel room only served to make it worse. He let out a shivering gasp through his parted lips and blinked away the tears in his eyes.

"Dean, I can't. I - I can't."

"You're a hunter, Sam. Of course you can. I'm - I'm just another monster now."

Dean dragged in a breath and pushed himself onwards.

"All I want - Sam, all I want to do is tear out your throat, bury my teeth in your artery and drink you dry. I'm not the Dean you knew anymore. I'll never be again. There's - there's nothing you can do. Nothing."

Sam shuddered to the sound of yet another scared laughter that Dean let out. He couldn't stay still, and rather than staying on the bed, he picked himself up again and walked to the middle of the room until the window's light reflected onto him, and Sam could see his pale complexion and the hunger in his eyes, the whole of him wasted and drained somehow, like he'd lost an unhealthy amount of weight in a matter of days. He glimpsed back at Sam and examined him before moving his fingers up to his lips and dragging the corner of his mouth up to show the newly-grown row of hook-like fangs in front of his human teeth, confirming how close he was to losing it already.

"No," Sam heard himself utter, "Dean, no."

"No?" Dean grunted, letting his lip fall back over his teeth, "Sam - I can't hold back forever."

"No," Sam repeated, "There's - there has to be another way."

" _What_ way, Sam? I can't be cured. I can't not feed. There's no other way. Kill me, Sam - or I'll walk out that door and that'll be the last you ever see of me, and you'll know that someone else, somewhere, did what you couldn't do. That the last thing I saw was some hunter who sees me as nothing more than a monster -"

"Dean, don't."

Sam stood up; he walked to his brother and grabbed his wrist, making Dean jump and try to back off a step from Sam's pulsing, living, warm body. He let out an indistinct sound and revealed his teeth for just a moment again before turning his head away, and Sam could feel him shaking.

"Remember, years ago, when we ran into Lenore?"

"Who?"

"The vampire who refused to drink human blood."

Dean tensed. He breathed funnily for a while before daring to turn his head back towards Sam, but Sam swallowed thickly at the sight of his eyes immediately seeking out Sam's throat instead of his eyes. It didn't last for long, however - soon enough, Sam could catch his brother's eyes, and he looked into them pleadingly, his grip over Dean's hand tightening.

"It can be done, Dean. You won't be the first one."

"Sam, you have no idea how this feels," Dean told him, and Sam knew it, he could hear it in his voice, but there was no way he'd let Dean go.

There was no way he'd kill him, either.

"You need food, but it doesn't _have_ to be human. You don't have to kill."

They stood there, Sam's hand wrapped around Dean's wrist and Dean standing there, still, his eyes flickering between Sam's throat and his eyes, for a very long time. Outside, a car parked on the motel's parking lot, and its headlights shone brightly through the window, revealing more of Dean for Sam to see. His hair was a mess and his clothes looked worn from a fight he'd had. There was a visible tear on his sleeve, and some blood still from where the vampires had drank from him. They'd played with him, Sam realised; there were teeth marks all over his throat on one side, hardly deep enough to drain him of all his blood, but enough for Sam to know that they'd either kept him for a long time or there had been many who'd fed from him in a short span of time before they'd eventually turned him. He couldn't blame Dean for wanting to die. The shock of the transformation alone would do it, but the thought of being turned by a pack that first used him like a toy before finally ending it like that - Sam's chest ached to the thought, and finally, he let go of Dean's wrist.

"You don't have to die," he told Dean firmly but in a quiet voice, as if wanting to keep this just between them, "And even then - I won't let you."

"I can't live like this," Dean countered, but Sam shook his head.

He turned his back to Dean despite the way it caused his hair to stand up all over his body, and walked to his bed again. He settled there with a sigh and when he looked, he found Dean standing a couple steps closer to him than before. A small smile lingered on his lips although he felt drained and empty inside.

"Where would I go?" Dean asked him after a short silence.

"Wherever you want. Wherever's... safe."

"You think that's worth it? Being forced to live alone forever, or at least until I inevitably get caught and killed anyway?"

"No," Sam said, "You won't have to be alone."

It was Dean's turn to tense, and Sam could see it happen and knew to expect it. His brother wasn't stupid. Of course he'd caught on.

"Sam -"

"Yeah. I don't particularly want to die alone, either," Sam chuckled, hanging his head and letting out a small sigh, "So... anytime you're ready."

"No. I won't. Sam, I _won't._ I came here to die. I didn't come here to kill _you_. I'll never - Sam, I can't do it. I won't."

"Think about it," Sam said with exasperation in his voice now, "You can't do this alone. I trust you when you say that, because it won't be easy. I _know_ fighting a desire like that... it's not, and it will never be, easy. But we're stronger together. We've always been. This family's all we've got. You think I don't feel that way, too? You think - you think I'd just move on after you're dead, or once you're gone? You think I could just let go?"

Dean's weight moved from one foot to the other, and Sam felt something else shift in him as he did so, too. He couldn't tell what it was yet, but it was a profound change, something that turned him... more predatory than he'd been before. More alert, more aware, more like a big cat prowling before an antelope. And Sam was the antelope. He was fine with that, however.

"So... have at it, Dean. Turn me, too. Then we can fight it together."

"Sam."

Sam kept his head down as Dean moved closer. His steps were silent so that not a sound could be heard as he walked the distance between them to the bed, and despite knowing he was there, Sam felt his body shake when Dean touched his shoulder and sat down on the bed next to him.

"I can't... say no," Dean told him in a weak voice, "but I want to, because this isn't right. I know this isn't right. If I was still me, I -"

"You are still you, Dean. You won't ever not be you. It'll be different, but I trust you - you've always been better than you give yourself credit for, you know."

Sam let out a small breathless chuckle and tilted his head back. Almost immediately, he felt the tip of his brother's nose brush against his neck, and - unexpectedly - it sent a shiver down his body. His heart picked up and he breathed out a tense sigh.

"Take what you need," he said, eyes closing, "Then turn me, and I'll do this with you, the whole mile."

"Forever?"

"What do you think?" he chuckled, peering out through half-lidded eyes with a small grin on his lips despite the fear filling up his veins.

Dean's eyes looked unfocused and glassy as he nodded, swallowing hard. The bite barely hurt - he was gentle with the way he let his fangs pierce Sam's skin, like a hundred needles puncturing into his artery at once. That was they way he led them out from Sam's body, too, only to replace the pain with the silky texture of his mouth, and he drank, sucking at the pulsing flow of blood flooding out through the wounds, and it took little time for Sam's dizziness to turn worse. He sought balance from the bed but his arm went out from underneath him, and it was Dean who caught him, holding him against his body as he drank, and despite the ache, Sam felt himself relaxing into his hold. He was giving in with no struggle - ultimately, it wouldn't matter much if he'd die there. But just as his consciousness was starting to fade, Dean's lips left his neck and pierced his own flesh instead. His wrist was wet with fresh blood as he pressed it to Sam's mouth, and it was Sam's turn to take that blood in. At first, his body wanted to reject it, and he had to suppress a gag and force himself to swallow instead, but after the first mouthful had gone down, he felt a strange appetite growing for more. It felt wrong; he could feel a heat in his body forcing him to suck harder, and it brought back memories from all the times he'd done the same with Ruby, and then went deeper and reached for memories much further back in his mind - memories of a time when he'd been very young, memories of a deep coppery taste on his lips from a shadow above him, and then nothing. He fell back and felt Dean's grip around him turning tighter as he faded, and the night turned even darker around him, until everything was pitch black and dead silent.

The next thing he recognised was the sunrise. Dawn was breaking behind the thin curtains, and as Sam opened his eyes feeling feverish and weak, the first thing he saw was Dean sitting beside him on the bed, humming one of his favourite songs a little off-key. He reached a hand towards him and his fingers dragged over Dean's back; the humming stopped, and Dean turned back to look at him with a tired smile. As Sam's hand fell back on the bed, Dean's moved into his hair and combed through them.

"How's it feeling, Sammy?" he asked in a low voice, the other side of his face painted with deep gold from the window above.

The light was starting to hurt Sam's eyes, but he smiled the best he could before closing his eyes again.

"I don't think it'll get better from here," he confessed.

"It won't. Trust me."

"Don't go."

"I'm not going anywhere anymore. You know that, right?"

Sam nodded. He was fading again: the bed underneath him seemed to rock gently as his mind gave up and turned blank, leaving him drifting between life and death. Through that haze, he felt Dean moving over him. He didn't understand it at first, but soon, he could feel Dean's fingers trail the waistband of his pyjama pants. Forcing himself back into the real world, he faced his brother's serious eyes above him.

"I've never felt anything like this," Dean told him, although he wasn't exactly sure what he was hearing through the mist that had taken over his senses, "Now that you're turning - it's... different."

"Different?" he repeated, eyes closing again.

"Yeah."  
Dean's fingers bent underneath the waistband and gently tugged at his pants.  
"Sammy, I... Are you there?"

"I'm not sure."

"There enough to tell me if this is alright?"

"Dean -"

"We mate for life. We only have to do this once, and then we'll be bound together. Fully, Sam. The way only... beings like us can be."

Sam forced his eyes open again. Breathing took most of his energy, and he still wasn't sure if this was really happening. His body, however, was responding; he felt hard and heavy inside his pants, and Dean's hand over his hip seemed to radiate warmth and promise redemption like nothing else could. He nodded, even if he wasn't sure if what Dean was saying made any sense.

"You want that?" he asked, his voice shaky and blank.

"I think so," Dean breathed out in response, his fingers gripping Sam's waistband harder, "I - my body wants it. I can smell you, Sam, so damn strong and - and it's doing something to me that I've never... really felt before."

Sam's eyes closed again, but he felt himself parting his legs for Dean.  
"Then do it," he said and his voice echoed in his ears.

His skin burned as Dean pulled down his pants. The next thing he knew was Dean's mouth around his sex, his lips tight around his shaft and the wet warmth of his mouth surrounding the crown of his cock. He let out a quiet moan and his fingers found Dean's hair; it felt vaguely dirty - this was his _brother_ \- but he couldn't muster the energy or the conscience to feel guilty. Everything was changing, his body was changing, he was somewhere between death and becoming something else than human, and somehow that seemed to make the human world with its arbitrary rules and regulations distant and unnecessary for him. He didn't belong in that world anymore. Neither did Dean; the only thing that mattered was _them._ Being together - forever.

He shifted his hips lazily towards Dean's mouth, and Dean let out a moan around his cock, and Sam could feel him swallow around it as he started working up and down along it. He wasn't sure how long it lasted, only that once it ended, his cock was aching hard and resting heavy over his hipbone, leaking, and Dean was somewhere else. He heard the floorboards creak as Dean stepped over them, he heard the bag's zipper, and he heard a snap and the sound of something wet squirting over Dean's hand, and then nothing again. Inside his ears was an ocean of blood, and through it all, he could no longer hear his heartbeat. It was gone, and some part of him knew he'd never hear it again, but he didn't feel cold or dead, only as if his whole body was on fire, and the sensation tingled all over his skin and made him gasp for air as Dean's index finger pressed against his tight hole. His leg was bent out of the way, the other still resting on the bed, and Dean was holding his thigh and pressing it against his stomach as he rubbed his finger over and into Sam's body, his skin and Sam's flesh now slick with lube or cream or whatever it was that he was wetting him with. Soon, his finger entered Sam, and his body pressed closer until their mouths were together, and Dean's lips were hungry as he claimed Sam's with them, and his tongue played with the smooth underside of Sam's lower lip and the curve of his upper lip as he lay there without realising that he could have responded to the kiss - or rejected it. He was constantly slipping under again, only barely staying conscious for short periods of time, and when Dean pushed his cock inside Sam, he could only moan in a muffled voice as his panting breaths filled his ears.

Dean rocked into him, his own gasps and grunts the soundtrack to Sam's transformation, and he had sex with him while Sam was struggling to stay aware of it. Every and each of his movements caused a shockwave of pleasure inside Sam's strange-feeling body, however; he was aware of this at least if nothing else, and Dean's reassuring lips moved onto his bruised neck that no longer bled nor felt open at all. He could feel something else happening to him as he lay there, receiving Dean's movements as they came: he could feel a strange bond forming between himself and his brother, one that bound itself to the way Dean's cock was stretching him open and pushing into his body. Sam could feel it becoming stronger and more physical with every thrust, and as his brother held his hips tight against Sam's own, he felt as if they were one in body and mind, like if he'd only been a little more aware, he could have listened in on Dean's thoughts. Then Dean moved away again, and his next thrust was harder, and the way he fucked Sam became more rough than gentle, leaving them both a mess of sweat and trembing gasps and moans. His teeth, the blunt human ones, bit Sam over the shoulders and his neck before turning to nails again, and the sharp needles raked his jaw and his Adam's apple never piercing his skin however, and Sam felt a strange, pinching sensation in his gums as his own newly-formed fangs came in and he buried them into Dean's shoulder, barely awake enough to hold up his own head. His body pulsed around Dean's cock, not with life but with some strange form of energy that now moved his muscles instead, and he wrapped his legs around Dean's hips and moved back and forth with him, pleasure and desire driving him madly onwards where his conscious mind still refused to take control. Their mouths joined again as Sam's back arched and he felt his seed spilling out and painting his stomach to the rhythm of steady pulses inside his body, and his eyes opened to a blurry view of his brother releasing above him - he felt his body fill up with Dean's come, and the sensation was strange and new for him but it sealed that odd unity that had began forming between them like glue, and it was that thought and feeling that drowned him out again and led him to a comforting, smooth silence and darkness in the midst of daylight pouring in through the window.

All the way until he woke up again, he could now sense his brother and his mate by his side, as reliably as a steep mountainside, never once moving away from him as long as he remained vulnerable.


End file.
